Total Iron Binding Capacity Test

A total iron binding capacity (TIBC) test is a type of blood test that gauges whether there’s too much or too little iron in your bloodstream.

Iron is a type of mineral found in all of the body’s cells. You get the iron you need through your diet. Once iron enters the body, it’s carried throughout your bloodstream by a protein called transferrin, which is produced by your liver. The TIBC test evaluates how well transferrin carries iron through your blood.

In your blood, iron helps form hemoglobin. Hemoglobin is an important protein in red blood cells that helps carry oxygen throughout the body so it can function normally. Iron is considered an essential mineral because hemoglobin can’t be made without it.

Males

Females

ages 9 to 13: 8 mg/day

ages 14 to 18: 15 mg/day

ages 19 to 50: 18 mg/day

ages 51 or older: 8 mg/day

lactating women ages 19 to 30 year: 9 mg/day

The Centers for Disease Control and Prevention recommends that pregnant females of all ages take 30 mg/day. Pregnant and lactating women may need different amounts of iron than those recommended. Check with your doctor to find out how much you need.

Your doctor may perform a TIBC test if you’re experiencing the symptoms of anemia, or a lack of iron in the blood. In the United States, iron is the most common type of dietary deficiency. Iron deficiency is usually the cause of anemia, but the condition may also be triggered by increased blood loss during menstruation, pregnancy, and chronic infections.

The symptoms of low iron levels include:

feeling tired and weak

skin pallor

an increase in infections

always feeling cold

a swollen tongue

difficulty concentrating at school or work

delayed mental development in children

A TIBC test may also be ordered if your doctor suspects you have too much iron in your blood. High levels of iron most commonly indicate an underlying medical condition. Some common causes of high iron levels include:

Fasting is required for a TIBC test to ensure the most accurate results. This means you shouldn’t eat or drink anything for at least eight hours before the test.

Some medications can also affect the results of a TIBC test, so it’s important to tell your doctor about any prescription or over-the-counter medications you’re taking. Your doctor may tell you to stop taking certain medications before the test. However, you shouldn’t stop taking any medications without talking to your doctor first.

A TIBC test may be ordered along with a serum iron test, which measures the amount of iron in your blood. Together, these tests can help determine whether there’s an abnormal amount of iron in your blood.

The tests involve taking a small sample of blood. Blood is usually drawn from a vein or artery in the hand or the bend of the elbow. The following steps will occur:

A healthcare provider will first clean the area with an antiseptic and then tie an elastic band around your arm. This will make your veins swell with blood.

Once they find a vein, they’ll insert the needle. You can expect to feel a slight prick or stinging sensation when the needle goes in. However, the test itself isn’t painful.

They’ll only collect enough blood as needed to perform the test and any other blood tests your doctor may have ordered.

After enough blood has been drawn, they’ll remove the needle and place a bandage over the puncture site. They’ll tell you to apply pressure to the area with your hand for a few minutes.

Normal values for the TIBC test can vary among laboratories. However, most laboratories define a normal range as 240 to 450 micrograms per deciliter (mcg/dL).

A total iron binding capacity value above 450 mcg/dL usually means that there’s a low level of iron in your blood. This may be caused by a lack of iron in the diet, increased blood loss during menstruation, pregnancy, or a chronic infection.

A total iron binding capacity value below 240 mcg/dL usually means that there’s a high level of iron in your blood. This may be caused by:

liver damage

iron or lead poisoning

frequent blood transfusions

hemolytic anemia, which is a condition that causes red blood cells to die prematurely

sickle cell anemia, which is an inherited condition that causes red blood cells to change shape

hemochromatosis, which is a genetic condition that causes a buildup of iron in the body

Your doctor will explain what your individual results mean for you and what the next steps should be.